Window Performance Data

Each year, the average American household spends $1,500–2,500 on energy bills. 45% of that cost is for heating and cooling. Choosing high-performance windows, doors, and skylights can save you money and keep your home comfortable.

Finding the right window or door, for your project, hinges on several style and performance factors. And while type, color, and material preferences will differ from person to person, high-performance products will result in the following:

Deliver comfortable levels of heat and light

Maintain a consistent temperature

Defend against UV radiation

One of our favorite resources when searching energy efficient window performance is the NFRC Website. The National Fenestration Rating Council helps homeowners find independent data to help in choosing the best window and door products for today’s home.

NFRC-certified products are independently tested, certified, and labeled to help you make the best purchase decision for your needs.

While the ENERGY STAR label tells you if a product is energy-efficient, the NFRC label helps you compare between energy-efficient products by breaking down a product’s energy performance.

What does the NFRC label tell you?

U-Factor measures how well a product can keep heat from escaping from the inside of a room. The lower the number, the better a product is at keeping heat in.

Range: 0.20–1.20

Look for: Low numbers

Solar Heat Gain Coefficient measures how well a product can resist unwanted heat gain, which is especially important during summer cooling season. The lower the number, the less you’ll spend on cooling.

Range: 0–1

Look for: Low numbers

Visible Transmittance measures how well a product is designed to effectively light your home with daylight, potentially saving you money on artificial lighting. The higher the number, the more natural light is let in.

Range: 0–1

Look for: High numbers

Air Leakage measures how much air will enter a room through a product. The lower the number, the fewer drafts you’ll experience.

Range: 0.1-0.3

Look for: Low numbers

The NFRC label helps you compare between energy-efficient windows, doors, and skylights by providing you with energy performance ratings in multiple categories.

Why is all of this important? When you replace windows and doors in your home, if you choose products without knowing their performance, how will you know if you are getting the best window for your home? Simple, take a look at the NFRC ratings for performance data